Machine and method for forming tubular adjustable elbows

ABSTRACT

A machine for forming tubular adjustable elbows has a frame on which are mounted split die shells opened and closed by a hydraulic jack and carrying split die rings having elliptical grooves. Axially within the die shells is an assembly of elastomeric elliptical rings opposite the grooves and interspersed with rigid spacers all movable together by a hydraulic squeezing jack effective to break an original integral tube into separate sections having beaded ends. Other hydraulic plungers telescope the sections together for further forming and interlocking by squeezing of the elastomeric rings to produce the final, sectional product. The method is carried out by starting with an integral circular-cylindrical tube, breaking the tube into separate sections along elliptical lines, enlarging or beading one end of some sections, telescoping the unbeaded ends into the beaded ends and then expanding the unbeaded telescoped ends into the surrounding beaded ends.

Unite States. Patent [191 Walker 1 1 June 11, 1974 [5 1 MACHINE AND METHOD FOR FORMING TUBULAR ADJUSTABLE ELBOWS [75] Inventor:

52 U.S.Cl 72/55,72/58,29/157 A,

r 72/370 51 lm. Cl B2ld 26/00, B21d39/O8 [58] Field of Search 29/157 A, 157 T, 416, 437; 72/61, 62, 58,370, 55, 59, 54; 113/116 UT [56] References Cited UNITED STATES PATENTS 1,835,314 12/1931 Lord 72/59 1,973,622 9/1934 Hand 72/58 2,306,018 12/1942 Fentress 72/59 2,458,854 l/l949 Hull 6! a1. 72/58 3,067,799 12/1962 Cooper et a1... 72/59 3,083,754 4/1963 De Mers l 72/59 3,189,991 6/1965 Moore 29/437 3,200,627 8/1965 Hoffmann 72/61 3,490,137 l/l970 Buck et al 29/157 A 3,595,047 7/1971 Fanning et al. 72/370 3,627,336 12/1971 Lawson 72/61 Primary Examiner-Charles W. Lanham Assistant Examiner-D. C. Crane Attorney, Agent, or FirmLothrop & West 5 7 1 ABSTRACT A machine for forming tubular adjustable elbows has a frame on which are mounted split die shells opened and closed by a hydraulic jack and carrying split die rings having elliptical grooves. Axially within the die shells is an assembly of elastomeric elliptical rings opposite the grooves and interspersed with rigid spacers all movable together by a hydraulic squeezing jack effective to break an original integral tube into separate sections having beaded ends. Other hydraulic plungers telescope the sections together for further forming and interlocking by squeezing of the elastorneric rings to produce the final, sectional product. The method is carried out by starting with an integral circularcylindrical tube, breaking the tube into separate sections along elliptical lines, enlarging or beading one end of some sections, telescoping the unbeaded ends into the beaded ends and then expanding the unbeaded .telescoped ends into the surrounding beaded ends.

12 Claims, 14 Drawing Figures PAIENrEDJuM 1 1914 Y 38151394 saw 1 or e INVENTOR. EDWARD WALKER fzzin r U4? ATTORNEYS PATENTEDJUN 1 1 m4 3 a 153 94 SHEET 20? 6 FIG 12 PATENTEDJW 1 m4 3815394 SHEEHUF 6 mm a I 3 mm 1mm PATENTEDJuu 1 new SHEEI 80? 6 J Q wN MACHINE AND METHOD FOR FORMING TUBULAR ADJUSTABLE ELBOWS Elbows customarily utilized with conduits for the conduction of gases such as air, and particularly with pipes made of sheet metal, are usually supplied either in a permanently formed, bent contour or, more particularly of interest in this case, in a form in which a round elbow tube is comprised of a number of sections, usually four. that are related to each other by interengaged beads lying in various planes all inclined to the original axis of the tube. The configuration of the beads is therefore elliptical because of theround contour of the tube sections themselves. The flexibility of the tube ma terial and the tolerance of the interrelated parts is such that the tube sections can be rotated manually with respect to each other to produce various angular attitudes of the tube sections relative to each other. What initially is a relatively straight tube lying along an axis can be conformed into an elbow of various different degrees of total effective curvature. Such elbows are generally referred to herein as tubular, adjustable elbows.

The fabrication of elbows of this type is still attended with a great deal of individual forming and developing accompanied by a lot of manual work in assembling and completing the elbows, and this has kept their cost Another object of the invention is to provide a machine for forming tubular adjustable elbows that can successfully utilize present materials and sizes currently available to afford tubular adjustable elbows similar to present products but automatically manufactured.

Another object of the invention is to provide a machine for forming tubular adjustable elbows that is simple and economical to construct and run and which can be operated without the use of more than semi-skilled labor.

Another object of the invention is to provide a machine for forming tubular adjustable elbows effective for relatively high rates of production.

A further object of the invention is to provide a method for forming tubular adjustable elbows from the usually utilized materials and capable of producing a commercially satisfactory product substantially without the use of any hand forming, assembling or adjust- An additional object of the present invention is to provide a method for forming tubular adjustable elbows that is a substantial and distinct improvement over methods currently employed.

Other objects of the invention together with the foregoing are attained intheembodiment of the machine and the practice of the method as set forth in the following description and as particularly illustrated in the accompanying drawings, in which:

FIG. 1 is a side elevation of one form of machine constructed pursuant to the invention, certain parts of the operating and control mechanism being omitted for clarity;

FIG. 2 is a plan of the machine of FIG. 1;

FIG. 3 is a cross-section to an enlarged scale showing much of the machine in front elevation and a portion of the structure in cross-section, the general plane of the view being indicated by the lines 33 of FIG. 2;

FIG. 4 is in part a plan with portions broken away to show the interior construction of the machine in crosssection along the line 4-4 of FIG. 3;

FIG. 5 is a view similar to FIG. 4 but showing the parts of the machine in cross-section on a vertical, axial plane;

FIG. 6 is an enlarged view in section on an axial plane showing a tube blank in position for the first step in forming;

FIG. 7 is a view similar to FIG. 6 but showing a successive step in tube formation;

FIG. 8 is a similar view in cross-section showing a successive step in tube formation;

FIG. 9 is a view of a similar nature but showing additional portions of the machine in cross-section on an axial plane and with parts of the forming structure broken away, the parts being illustratedin position prior to assembly; I

FIG. 10 is a view similar to FIG. 9 but showing the parts in a successive position of assembly;

FIG. 11 is a similar view showing the parts in a final position of assembly;

FIG. 12 is a diagrammatic side elevation of a sheet metal tube in starting condition;

FIG. 13 is a view similar to FIG. 12 but showing the tube in finally formed condition; and

FIG. 14 is a side elevation of the tube of FIG. 13 as an elbow in one of its operating positions.

The machine and method as disclosed herein can be incorporated and practiced in a widely variant number of ways, but in the present instance a device has been successfully manufactured and-the method has been successfully carried out in connection with a starting tube 6, as shown in FIG. 12. This is of any size but usually is of approximately the ratio of diameter to length shown. In a practical example, a starting tube is about 6 inches in diameter and is about 12 inches long. The initial tube 6 can be a solid member such as is provided by a very thin-walled extrusion or, more frequently, the tube is initially made from a flat, thin metal sheet roller into tubular form -with a joint 7 usually not abutted but slightly overlapped and held together either by spot welding, a folded and interlocked seam, by rivets, or even by adhesives. It is generally immaterial what the precise nature of the starting tube 6 is so long as it is substantially circular-cylindrical about an axis 8 and so long as the material of the starting tube is of the usual sort amenable to the requisites of the machine and method. Ordinary sheet iron or sheet steel, galvanized or not, and aluminum have been found to be appropriate.

The machine includes a base frame 11 in the form of a housing containing a power-driven source of hydraulic fluid under pressure and subject to operator control. The hydraulic mechanism is not illustrated in detail since it is of a generally recognized character. The base frame. 1 1 is contoured and dimensioned to afford a suitably rigid and stiff base and housing for the remaining structure. Disposed on the frame 11 and situated to be generally symmetrical about a force and aft, horizontal axis 12 are semi-cylindrical die shells 13 and 14. These are quite similar in construction, so that except where v noted the description of one applies equally to the other. The die shells 13 and 14 are substantially semicircular in end elevation and are provided with reinforcing ribs 16 and 17. These are extended to provide journals encompassing a through journal pin 18 serving as a hinge mount, so that the die shells 13 and 14 are capable of relative rotation about a second axis 19 parallel to the first axis 12. The pin 18 is engaged with pairs of links 21 pivotally engaging second pins 22 (FIG. 3) secured to a fixed portion 23 of the machine base frame 11, thus permitting some transverse horizontal motion of the pin 18.

In order to actuate the upper die shell 13 and the lower die shell 14 in unison and in a floating fashion,-

there is provided a hydraulic jack 26 including a cylinder 27 having at its upper end a pair of upstanding plates 28 each carrying a pivot pin 29, the ends of which are disposed in extensions 31 of ribs 32 reinforcing the lower die shell 14. Reciprocable by hydraulic pressure within the cylinder 27 and also forming part of the jack 26'is a piston 33 joined to a piston rod 34 upstanding above the cylinder 27 and having a block pivoted to a cross pin 36 engaging a pair of extensions 37 reinforcing and forming part of the upper die shell 13.

- With this arrangement, when hydraulic fluid is introduced beneath the piston 33 into the cylinder 27, the upper and lower die shells are spread apart or opened, pivoting about the axis 19 of the pivot pins 18 with a certain freedom of lateral or transverse movement due to the support of the pivoted links 21. When the pressure situation is reversed and hydraulic fluid is brought into the cylinder 27 above the piston 33, the die shells are brought toward each other, again with a certain amount of lateral movability, so that the arcuate movements involved can readily be accommodated and so that in closed position particularly the two die shells accurately mate concentric with the axis 12. While no details of the hydraulic structure are shown, it will be appreciated that the cylinder 27 is fed at opposite ends through flexible hoses in the usual fashion so that the floating actuation referred to can readily be accomplished.

The interior construction and arrangement of the die shells is of particular interest, and since they are both nearly alike, a description of one applies generally to the other.

As particularly shown in FIG. 5, within the lower die shell 14 there is provided a central, split die ring 41. This is substantially a half circle in circumferential extent and occupies a part of the total length of the die 'shell' 14. There is a corresponding split die ring 42 in the upper die shell 13 in a central location and extending for substantially the other half of the total die ring circumference. The central split die 41 is preferably held in axial position by a dowel pin 43 and the split die ring 42 is held in position by a dowel pin 44. When the unit is closed the two half rings 41 and 42 constitute a complete circumferential die. Both halves 41 and 42 of the die ring are contoured to provide an internal circumferential groove 46, half in each of the split die rings. The groove is of a particular axial cross-sectional configuration, as referred to hereinafter, and is positioned with its plane not at right angles to the axis 12 but inclined thereto as particularly shown in H6. 5, for example. This oblique section of a circular figure affords a groove that is substantially elliptical in its plane.

In a similar fashion there is also located in the die shell 14 at one side of the central split die ring 41 an additional split die ring 46. having a mate 48 in the other die shell 13. These split die rings are not anchored, but are free to move axially, although they are constrained against circular or rotary movement within their individual die shells. In this instance the combined split die rings 47 and 48 have their interior surfaces configured to define an internal circumferential groove 49 quite similar to the groove 46. The general plane of the groove 49 is not perpendicular to the axis 12, but preferably is tilted in the opposite direction from that of the groove 46.

In a comparable fashion, there is also located within the two die shells 13 and 14 a lower split die ring 5-] and an upper split die ring 52. These are mates and are disposed for limited axial movement within the die shell but are constrained against any rotation with respect thereto. The split die rings 51 and 52 are provided, considered together, with an internal circumferential groove 53 similar to the groove 49 and inclined to the axis 12 in substantially the same direction but opposite in inclination to the groove 46.

Since it is sometimes desired to shift the two end sets of split die rings toward the central set of split die rings, hydraulic means for that purpose are provided. The upper die shell 13 at one end is provided with a pair of hydraulic plunger mechanisms 56 and 57 and the lower die shell 14 is provided with a similar pair of hydraulic plunger mechanisms 58 and 59. This arrangement is duplicated at the opposite end of both die shells, so that there are eight of the hydraulic plunger mechanisms, four at each end of the structure. All of the plunger mechanisms are connected together hydraulically. As typically shown in FIG. 4, a flexible hydraulic line 61 leads into a chamber 62 within the mechanism 59, for example, secured to the end of the adjacent die shell by an appropriate fastening 63. Within the chamber 62 there is a sealed plunger 64 subject to hydraulic .pressure and abutting a half ring 66 in end alignment with the split die rings 51, 41 and 47. The remaining plunger mechanisms are similarly connected to abut the adjacent portions of their adjacent similar rings 66. The split die rings and the abutting rings 66 are normally urged apart by groups of springs 67, 68 and 69, so that the abutting rings 66 are held in contact with the adjacent plungers 64. When hydraulic pressure is exerted on the plungers, they move toward the center of the adjacent ring assembly and notonly are themselves translated but likewise compress the springs as the split die rings axially approach each other. When the hydraulic pressure is released, the springs thennot only spread the split die rings axially apart, as before, but likewise restore the rings 66 and the plungers 64'to their other, spread positions.

Mounted on the base frame 11 concentrically with the axis 12 is a hydraulic cylinder 71 including a sleeve 72 resting on a steady rest 73 upstanding from the base. Projecting from the head of .the cylinder 71 is a guide 64. slidable on an upstanding way 76 secured to the base 11 and confined for limited axial motion by a pair of antifriction rollers 77 and 78. Springs 79 are interposed between the cylinder 71 and the steady rest 73, being guided by appropriate studs 81, so that the cylinder mechanism is urged toward the right in FIG. 5 under normal circumstances.

Within the cylinder 71 there is disposed a piston 82 having a piston rod 83 extending entirely through the die shells along the axis 12 and extending far enough forwardly to receive a large exposed nut 84. Lying against the nut 84 concentrically with the axis 12 and within the die shells is a metal annulus 86 of slightly smaller outside diameter than the inside diameter of the ring 66 and of the various die split rings 51, 41, 47, 52, 42 and 48. The annular space between the ring 86 and the various dies all along the inside of the die shells is generally designated 87. Next to the annulus 86 there is an elastomeric ring 88 of substantially the same normal diameter and of an axial length somewhat greater than the groove 53, to which it is opposite, the elastomeric ring 88 being skewed or slanted in order that the groove 53 despite its inclination be equally and adequately covered. Alongside the elastomeric ring 88 is a special annulus 89 of relatively rigid or undeformable' steel like the ring 86, which also is not easily deformable. Adjacent the annulus 89 there is another elastomeric ring 91 inclined to cover the groove 46 for its entire circumference and extending to an adequate distance on either side thereof, yet being of sufficiently small diameter not to intrude into the annular space 87.

Next to the elastomeric ring 91 there is another rigid steel annulus 92 and adjacent the annulus 92 there is an elastomeric ring 93 disposed to cover the groove 49 adequately. Finally, there is an annulus 94 of steel which has a perpendicular end face abutting a thrust washer 96 at the end of the cylinder sleeve 72. The parts of this series are arranged so that the rigid rings have inclined faces to meet the corresponding inclined faces of the yielding, elastomeric rings so that there is full circular contact and even pressure distribution.

With this mechanism, when pressure fluid is admitted to the cylinder 71 on the right-hand side (inFIG. 5) of the piston 82, the floating cylinder is urged toward the right and the piston and its rod 83 are urged toward the left so that the various die members are in substantially the positions shown in FIGS. 4 and 5 and are their maximum distance apart with little or no axial compression or force between them. However, when hydraulic pressure is released from the right side of the piston 82 and is impressed on the left side thereof, as seen in FIG. 5,- then the cylinder 71 is translated toward the left and the piston 82 is translated relatively toward the right. This means that the nut 84 and the thrust plate 96 approach each other and everything in between them is squeezed axially together. This motion is quided and the parts during this axial movement are supported by a tubular cage 97 immediately adjacent the various elastomeric rings and their intervening annular spacers, the cage 97 having bearings 98 and 99 engaging the piston rod 83, so that all of the movable parts are supported in concentric relationship and are free for rela tive axial translation.

Advantage is taken of the ring motion to form a sleeve. Using as an example the split die ring 41 and the groove 46 opposite the elastomeric ring 91 and adjacent the spacers or annuli 89 and 92, and with an appropriate tube 6 in position, what occurs under pressure is particularly illustrated in FIGS. 6, 7 and 8. The groove 46 has a generally semicircular cross-sectional surface 101 merging with the internal surface 102 of the ring 41. This internal surface is generally half of a circular cylinder concentric in one position with the axis 12. However, the surface is differently contoured does merge abruptly with the surface 102 to define a When the nut 84 and the thrust washer 96 are urged together to squeeze the intervening parts, the substantially nondeflectible spacers such as 86 and the like cannot change their shape, although they may change their'axial positions, but the intervening elastomeric rings such as 88, 91 and 93 are urged to change their.

configuration. Since each ring is confined on the inner face by the rigid tubular cage 97 and on both sides by the metal annuli, the elastomeric material can only move outwardly or extrude into the grooves 46, 49 and 53.

sharp shoulder 108. Spaced slightly from the sharp shoulder is a countersunk band 109 having an end shoulder ll-l leaving'another abrupt ridge 112.

In the operation of this part of the structure, and this is true of all of the similar grooves, when the annuli 89 and 92 are urged toward each other by the hydraulic cylinder 71 and piston 82, as seen in FIG. 6, the rigid annuli 89 and 92* tend to approach each other uniformly toward the center of the figure. The elastomeric ring 91 is thus put under pressure and, since it has no other way to move, is displaced outwardly or downwardly into the groove 46. The metal of the tube 6 intervenes and, being locally unsupported, yields substantially as shown in FIG. 7. The tube is locally expanded and bends into the groove 46 with a smooth,

relatively low-stressed area to the right-hand side over the curved margin 103. At the same time the tube is given a very highly-stressed, sharp bend at the left-hand side over the sharp edge 108.

Depending upon the pressure exerted, the nature of the material of the tube 6, the' amount of lubrication, the temperature, and a number of other factors, the material of the tube 6 when'in the position shown in FIG. 7 is substantially deformed. It is somewhat elongated, pulled and subjected to a high-stress concentration in tension at the edge 108. What then occurs upon the exertion of even more pressure by mutual approach of the annuli 89 and 92 and further displacement of the elastomeric ring 91 is shown particularly in FIG. 8. At

some point between the position of FIG. 7 and FIG. 8 the stress on the material adjacent the sharp corner 108 is sufficiently high so that the material of the tube fails and fractures. The precise nature of this failure is not thoroughly understood since under various conditions it seems to partake of a failure in tension, there seems to be also a factor of shear, and there may be some fatigue. Whatever its cause and nature, this event is referred to herein as a break.

In any event, the metal breaks and parts, typically as shown, so that the original integral sleeve 6 finally has one portion 113 as seen at the left of FIG. 8 and another, separate portion 114 as seen at the right in FIG. 8. The formerly integral zones separate and pull to provide an intervening space 116 between the end surface 117 of the portion 113 and the end surface 118 of the portion 114. These surfaces l17 and 118 are a substantial distance apart because the material of the tube 6 is further strained and distorted and displaced by the imposed pressure to lie against the surface of the groove 46. In doing so the portion 114 of the tube 6 becomes circumferentially enlarged and has a substantially greater diameter than that of the original tube. The break shown in section in FIG. 8 is continuous around the entire periphery of the tube 6 and is also coincident with the inclined plane of the groove 46, so that the two spaced surfaces 117 and 118' lie closely in parallel planes ihclined with respect to the'central axis 12 when the break has occurred and when expansion and finishing of the portion 114 has been completed. Should the tube have an axial seam, the described action occurs at the seam as well, for the pressure used is sufficient to deform more than one metal thickness.

In addition to the bead formation and severance, the tube is also slightly displaced into the countersunk portions 104 and 109 by the elastomeric ring. At the end of this operation the left-hand tube portion 113 has a slightly enlarged neck 119 and an adjacent band 121 of substantially the original diameter. The right-hand tube portion 1l4 has an external bead 122 and a gently curved transition section 123 leading to a swell 124 adjacent the section 114 of original diameter. The breaking and configuration of the original tube 6 occurs uniwhich is still substantially of its original diameter, toward and into and in an overlapping relationship with the portion 122. This telescoping operation occurs all around each one of the sections and at both ends thereof throughout the entire length of the dies. When the parts have arrived substantially in the positions shown in FIG. 10, the approaching movement of the plungers 64 is stopped by release of the hydraulic pressure. but the dies do not change position since they are interlocked with the beaded or deformed tubular members. and the springs do not have adequate force to produce return translation.

At this junction and as the next step, hydraulic fluid is again admitted to the hydraulic cylinder 71 on the left-hand side of the piston 82 and forces another squeezing operation. This again displaces in the former fashion the elastomeric rings such as 91, and the elastom'er in displacing forces the portion 121, and similar formly and substantially simultaneously at each one of the various grooves 46, 49am! 53, so that at the conclusion of this operation the original, integral, circularcylindrical tube or sleeve 6 is actually in four separate sections, three of which at their left-hand ends have enlarged beads like 122 and three of which at their other ends have portions of the original diameter like 121.

Following the squeezing operation just described and accomplished by the hydraulic pressure acting against the left end of the pistion 82 and the left end of the cyl inder 71, that pressure is completely relaxed and the nut 84 returns toward its extreme left-hand position, while the cylinder 71 returns toward its extreme righthand position under the influence of reversed hydraulic pressure, the .parts during the squeezing operation and thereafter in effect floating and f nding their own end points and their own central positions. When pressure reversal has been concluded the elastomeric rings have resumed their original, generally rectangular crosssection, thus moving the intervening annuli apart, and the various split die rings remain in their original position, This condition of the parts is substantially as shown in FIG. 9.

As the next step, hydraulic pressure is exerted against all of the-plungers 64 which are pressed against the rings 66."The end die rings 51 and 47 are thus urged toward eachother and toward the intervening die ring 41. The end rings 66 are both particularly provided 1 with inturned flanges 126 effective to abut the ends of the tube 6. As the rings 66 under hydraulic pressure are forced toward, each other, the flanges 126 abut the'ends of the adjacent portions of the tube 6 and urge these portions toward 'each other. As particularly shown in FIG, 9, at the start of the operation the sections 113 and 114 are in their broken, spaced-apart location. However, as the rings 66 approach each other, there is an axial or endwise displacement of the part 1133, although the part 114 remains relatively stationary since it is interlocked with the die groove of the split ring. The endwise displacement forces the broken end 121,

portions, outwardly and into the'bead 122, or similar beads. There is a deformation of the part 121 against the interior of the bead 122 acting as a die and backed up by the wall of the groove 46. The parts eventually interlock substantially as shown in FIG. 11. The interlocking takes place substantially simultaneously around the entire circumference of the tube and in each one of the die groove locations.

When the foregiong deformation has been completed, the hydraulic pressure is reversed in the cylinder 71. The cylinder is restored to its relaxed, righthand position, and the pistion 82 is restored to its relaxed left-hand position. No compressive force remains on the elastomeric material, except that due to interlocking or friction with the formed tube, which is then ready correspondingly to retreat to its generally cylindrical condition as shown in FIG. 9. At this juncture the initially circular-cylindrical, continuous or integral tube 6 has been converted into the tubular adjustable elbow structure as shown in FIG. 13, losing something in its length in the process, being still symmetrical about the axis 12 but having four sections instead of one, with each section being rotatable relative to its neighbor, The shape of FIG. 14 or other, comparable shapes can readily be attained.

Since the material has been fully formed, the hydraulic load on the piston 33 and cylinder 27 is reversed, and the die shells I3 and 14 are separated, removing the various split die rings from contact with the formed member, which then lies rather loosely on the elastomeric rings and the intervening spacer or annular rings. When the forming members are released from the formed tube, then the elastomeric material and the intervening ring spacers, and the split rings aided by the springs 67, 68 and 69, return freely to their original axial locations. Since the nut 84 is somewhat similar in outside diameter than the inside diameter of the completed unit, it is easy to remove the unit axially from the machine. The operation is repeated for each device to be formed.

While, as considered above, the feeding of the initial shell 6 is done by hand and the removal as just described is done by hand, it is preferred that an automatic feeder be provided for moving the initial shell 6 axially into position over the elastomeric and annular members and for extracting the completed product from that position in the machine whenit is done. For

that reason, at one end of the die shells 13 and 14 and the nut 84 are provided with reliefs 131 and 132, leaving a portion of the adjacent ends of a contained sleeve or tube 6 exposed This area may be entered by means for handling the tube.

As particularly shown in FIGS. land 2, the base frame 11 carries extending brackets 133 on either side of center supporting guide rods 134 and 136. Slidable on the guide rods is a travelling head yoke 137 having a central depending portion 138 secured to the end of a piston rod 139. This extends into the base frame 11 and into a hydraulic cylinder (not shown) appropriately, controlled and arranged so that the yoke 137 is reciprocated between an extreme position as shown in FIGS. 1 and 2, at the left, and another extreme position at the right end of the brackets 133.

Outstanding from the ends of the brackets 133 are support rods 141 and 142 disposed at the proper spacing and height-to support a tubular blank 6 with its axis coincident with the axis 12. A suitable transverse feed for the blanks'6 can be provided in the usual way, so that a tube 6 can be deposited to be centered between the guide rods 134 and 136 and rest on the rods 141 and 142 in proper alignment.

Disposed on each side of the yoke 137 are similar pairs of tongs 143 and 144; The outer onesof the tong pairs are mounted on hydraulic cylinders 146 on the yoke 137, while the inner tong pairs are mounted on the piston rods 147 of .pistons (not shown) operating in the cylinders 146 under hydraulic control. in the operation of this device, after a tube 6 has been brought into the position shown in FIGS. 1 and 2 and has come to rest in axial alignment, the tongs 143 and 144 in open position are advanced, toward the right in these figures, by operation of the piston rod 139 until such time as the tongs are substantially opposite the end of the tube 6. Thereupon the cylinders 146 and piston rods 147 are actuated to bring the tongs together to grasp the end of the tube. Appropriate axial spacing is achieved by shoulders 148 on the outer tongs. Continued advance of the piston rod 139, to the right in FIGS. 1 and 2, moves the tube 6 into a final position with the ends of the sleeve adjacent the flanges 126 on the rings 66. During this time the right end of the tong pairs enters into the relieved portions 131 and 132. When the blank has been appropriately positioned the hydraulic cylinders'l46 are actuated in the reverse sense, the tongs are spread apart, and then by reverse action of the piston rod 139 the yoke 137 is restored to its extreme lefthand position as shown in FIGS. 1 and 2, ready for a subsequent use and leaving the tube blank in position.

The breaking and forming operation previously described is then completed by the die portion of the machine. When the product is finished it is withdrawn from the die portion of the machine by again moving the tongs in a similar fashion to project them into the relieved portions 131 and 132 on opposite sides of the adjacent end of the product, whereupon the cylinders 146 are again actuated so that the tongs grasp the near end of the product. When the dies are opened the piston rod 139 again moves toward the left, extracting the finished product from the machine into a position substantially as shown in FIGS. 1 and 2. Thereupon the tongs are again opened and retreat somewhat further to.

clear the finished product. This is then tumbled off of its support on the rods 141 and 142 to one side of the machine, while a new blank for subsequent operation arrives on the rods 141 and 142 for a repetition of the operation just described.

What is claimed is:

1. A machine for forming tubular adjustable elbows comprising a frame, a pair of die shells arcuate about a first axis, means for mounting said die shells for movement on said frame between a first open position with said die shells apart and a second closed position with said die shells together, a plurality of split die rings axially spaced inside said shells and defining the outside of an axial tube space, said split die rings each having an internal circumferential groove therein, elastomeric rings inside said die rings opposite said grooves and defining the inside of said axial tube space, a tubular cage inside said elastomeric rings, means for axially squeezing said elastomeric rings sufficiently to break a tube in said tube space into a plurality of axially separate portions, and means for moving said plurality of separate portions axially toward each other.

2. A machine as in claim 1 in which at least one of said die rings has an abrupt edge'defining one margin of said groove.

3. A machine as in claim 2 in which said die ring has a smoothly curved edge defining the other margin of said groove opposite said one margin.

4. A machine as in claim 1 in which said means for moving said separate portions axially relative to each other includes hydraulic plungers and springs opposed to said plungers.

5. A machine as in claim 1 in which said means for mounting said die shells for movement includes means for pivoting said shells together about a pivot axis parallel to said first axis, and means for establishing said pivot axis in various positions relative to said frame.

6. A machine as in claim 1 in which there is a pluralityof said split die rings axially spaced inside said shells, said means for moving said plurality of die rings includes yieldable means for urging said die rings axially apart, and superior means for urging said plurality of die rings axially together.

7. A machine as in claim 1 including a plurality of said split die rings axially spaced inside said shells, said die rings each having one of a group of internal elliptical differently inclinedgrooves, and a plurality of said elastomeric rings axially spaced each inside one of said die rings, and non-deformable spacer rings disposed axially between said elastomeric rings.

8. A machine as in claim 1 in which said means for squeezing has sufficient power to displace pan of a tube section originally in said tube space into said groove far enough to break and separate said part of said tube section from the remaining part thereof.

9. A machine as in claim 1 in which said die ring groove has a predetermined radial depth and a predetermined axial extent to receive a part of a tube section displaced by said elastomeric ring radially outwardly and broken away circumferentially from the remainder of said tube section.

10. A machine'for forming tubular adjustable elbows comprising a frame, die shell structure arcuate about an axis, a plurality of split die rings, means for mounting said die rings for axial movement relative to said frame and inside said shell structure thereby defining the outside of an axial tube space adapted to receive a plurality of axially separate tube portions, said split die rings each having an internal circumferential groove therein, elastomeric rings inside said die rings opposite said grooves and defining the inside of said axial tube space, a tubular cage inside said elastomeric rings, means for axially squeezing said elastomeric rings, and means in position for moving said plurality of tube portions relative to said frame and vaxially toward each other into overlapping telescoped relationship.

11. A machine for forming tubular adjustable elbows comprising a frame, a plurality of split die rings concentric with an axis, means for mounting said die rings for axial movement relative to said frame, said die rings each having an internal circumferential groove therein,

elastomeric rings inside said die rings opposite said grooves and radially spaced from said rings to leave an intervening space for an axially extending tube, means for axially squeezing and releasing said elastomeric rings to protect radially toward and away from said grooves thereby deforming said tube into axially separate portions, and means engaging at least some of said die rings and said tube portions for moving said die rings and at least some of said tube portions relative to said frame and toward each other.

12. A machine as in claim 11, in which said elastomeric rings define the inside of a tube space, and means on said frame for changing the axial length of said tube space and axially sliding at least one of said tube portions over at least one of said die rings 

1. A machine for forming tubular adjustable elbows comprising a frame, a pair of die shells arcuate about a first axis, means for mounting said die shells for movement on said frame between a first open position with said die shells apart and a second closed position with said die shells together, a plurality of split die rings axially spaced inside said shells and defining the outside of an axial tube space, said split die rings each having an internal circumferential groove therein, elastomeric rings inside said die rings opposite said grooves and defining the inside of said axial tube space, a tubular cage inside said elastomeric rings, means for axially squeezing said elastomeric rings sufficiently to break a tube in said tube space into a plurality of axially separate portions, and means for moving said plurality of separate portions axially toward each other.
 2. A machine as in claim 1 in which at least one of said die rings has an abrupt edge defining one margin of said groove.
 3. A machine as in claim 2 in which said die ring has a smoothly curved edge defining the other margin of said groove opposite said one margin.
 4. A machine as in claim 1 in which said means for moving said separate portions axially relative to each other includes hydraulic plungers and springs opposed to said plungers.
 5. A machine as in claim 1 in which said means for mounting said die shells for movement includes means for pivoting said shells together about a pivot axis parallel to said first axis, and means for establishing said pivot axis in various positions relative to said frame.
 6. A machine as in claim 1 in which there is a plurality of said split die rings axially spaced inside said shells, said means for moving said plurality of die rings includes yieldable means for urging said die rings axially apart, and superior means for urging said plurality of die rings axially together.
 7. A machine as in claim 1 including a plurality of said split die rings axially spaced inside said shells, said die rings each having one of a group of internal elliptical differently inclined grooves, and a plurality of said elastomeric rings axially spaced each inside one of said die rings, and non-deformable spacer rings disposed axially between said elastomeric rings.
 8. A machine as in claim 1 in which said means for squeezing has sufficient power to displace part of a tube section originally in said tube space into said groove far enough to break and separate said part of said tube section from the remaining part thereof.
 9. A machine as in claim 1 in which said die ring groove has a predetermined radial depth and a predetermined axial extent to receive a part of a tube section displaced by said elastomeric ring radially outwardly and broken away circumferentially from the remainder of said tube section.
 10. A machine for forming tubular adjustable elbows compRising a frame, die shell structure arcuate about an axis, a plurality of split die rings, means for mounting said die rings for axial movement relative to said frame and inside said shell structure thereby defining the outside of an axial tube space adapted to receive a plurality of axially separate tube portions, said split die rings each having an internal circumferential groove therein, elastomeric rings inside said die rings opposite said grooves and defining the inside of said axial tube space, a tubular cage inside said elastomeric rings, means for axially squeezing said elastomeric rings, and means in position for moving said plurality of tube portions relative to said frame and axially toward each other into overlapping telescoped relationship.
 11. A machine for forming tubular adjustable elbows comprising a frame, a plurality of split die rings concentric with an axis, means for mounting said die rings for axial movement relative to said frame, said die rings each having an internal circumferential groove therein, elastomeric rings inside said die rings opposite said grooves and radially spaced from said rings to leave an intervening space for an axially extending tube, means for axially squeezing and releasing said elastomeric rings to protect radially toward and away from said grooves thereby deforming said tube into axially separate portions, and means engaging at least some of said die rings and said tube portions for moving said die rings and at least some of said tube portions relative to said frame and toward each other.
 12. A machine as in claim 11, in which said elastomeric rings define the inside of a tube space, and means on said frame for changing the axial length of said tube space and axially sliding at least one of said tube portions over at least one of said die rings. 